| With the development of industries such as automobiles,communications,rail transit,and aerospace,aluminum alloy products are required to be large,complex,and thin-walled.Traditional aluminum alloy materials are limited to their low hardness,wear resistance,and high linear expansion coefficient.And the large volume shrinkage rate can no longer meet the performance requirements.The reinforced particles of in-situ aluminum matrix composites are generated inside the melt,and the size of the reinforced phase is small,uniformly distributed,and the bonding strength with the matrix is high.The strength and toughness of particle reinforced aluminum matrix composites are much greater than that of traditional aluminum alloy improve.The main research content of this article is divided into two parts.The first half adopts the mixed salt(LSM)reaction method.First,pure aluminum is used as the base alloy,and the KBF4,K2Ti F6 mixed salt reaction system is selected to study the reasonable preparation process parameters and successfully prepare TiB2 After/Al composite material,TiB2/6061 aluminum matrix composite material is prepared according to the process parameters and its structure and properties are studied;a reasonable heat treatment process is designed to study the structure and properties of TiB2/6061 aluminum matrix composite material after heat treatment.The specific conclusions are as follows:(1)The influence of stirring and dispersant Ce O2 on the preparation process of mixed salt method was studied,and the optimal preparation process parameters were determined.Finally,TiB2/6061 aluminum with different mass fractions(1wt%,3wt%,5wt%)were successfully prepared Matrix composite material,and the reinforcement particles are evenly distributed without agglomeration.(2)The mechanical properties of the prepared composite material were characterized and tested.The results showed that the hardness,tensile properties,and wear resistance of the composite material were significantly improved compared to the 6061 aluminum alloy matrix.The hardness of the 5wt%TiB2particle-reinforced composite material reaches 76HB,which is 38.2%higher than the hardness of 6061 aluminum alloy;the tensile strength of 5wt%TiB2/6061aluminum matrix composite material reaches 209MPa,which is stronger than the6061 aluminum alloy matrix.The tensile strength is increased by 56MPa;the wear rate of 5wt%TiB2/6061 aluminum matrix composites has decreased by about34.5%.(3)The changes in the microstructure and hardness of the composites with different solution temperatures and the same solution temperature and different solution times under the same solution time were studied,and the optimal solution treatment process was determined to be 535?/4h;The change of the microstructure and hardness of the composites at different aging temperatures at the same aging time and at the same aging temperature with different aging time determines the best aging treatment process to be 175?/9h.(4)The hardness and tensile performance test results show that the strength of the heat-treated material has been significantly enhanced.Among them,the tensile strength of 1wt%,3wt%,and 5wt%TiB2/6061 aluminum matrix composites after heat treatment reached 278MPa,304MPa,and 316Mpa,respectively.After heat treatment,the wear rate of the four materials decreased,and the wear rate of the materials decreased with the increase of the reinforcing particle mass fraction.Among them,the wear rate of the 5wt%TiB2/6061aluminum matrix composite material decreased from 11×10-9m3 to 4×10-9m3.(5)During the forging process of the composite material,some of its casting defects are eliminated and the structure is more uniform and dense,thereby improving the mechanical properties of the material.The tensile strength of the composite material after forging heat treatment reached 284 MPa,306 MPa,323MPa,and 347 MPa,respectively,while the elongation change of the material was similar to the heat treatment change trend of the unforged composite material,with a slight decrease,and the range of change was not large. |
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